diff --git a/common/mbox-util.c b/common/mbox-util.c
index c451198c2..90722757d 100644
--- a/common/mbox-util.c
+++ b/common/mbox-util.c
@@ -18,6 +18,10 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
+/* NB: GPGME uses the same code to reflect our idea on how to extract
+ * a mail address from a user id.
+ */
+
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/doc/DETAILS b/doc/DETAILS
index dc8ba1f7a..332e686f2 100644
--- a/doc/DETAILS
+++ b/doc/DETAILS
@@ -701,7 +701,8 @@ pkd:0:1024:B665B1435F4C2 .... FF26ABB:
     This status identifies the key and the userid for all following
     Tofu information.  The fingerprint is the fingerprint of the
     primary key and the mbox is in general the addr-spec part of the
-    userid encoded in UTF-8 and percent escaped.
+    userid encoded in UTF-8 and percent escaped.  The fingerprint is
+    indentical for all TOFU_USER lines up to a NEWSIG line.
 
 *** TOFU_STATS <validity> <sign-count> 0 [<policy> [<tm1> <tm2>]]